Jump to content
  • Welcome Guest To Mopar1973Man.Com

    We are a Dodge Ram Cummins Turbo Diesel forum. We are very friendly and helpful group of Dodge Ram Cummins owners. We will try to keep your truck running the best we can and provide information for diagnostics, repairs and even guide you on the best replacement parts to use. 

     

    Registration is free. Registering on the site will provide access to many more things like...
     

    • Contribute to the Forum being able to ask questions and get support for your Dodge Ram Cummins.
    • Contribute to Article Database adding your ideas and suggestions.
    • Classified Ads posted by the members. Post up your used parts and vehicles.
    • Member Garage where you can proudly display your vehicles and modifications that you have done to them.
    • Download files, documents, and Quadzilla Adrenaline tunes for your truck.
    • 911 Support Network. We've got a group of members will to aid you if your truck breaks down on the road.

Sign in to follow this  
ISX

Speed/RPM calc..

Recommended Posts

Spent a while making this thought you guys could have some fun with it too. You have to have microsoft excel for this file to work. Should work with any version.Don't mess with anything but the highlighted blue things or you might erase my formulas. If you do manage to delete it all and make it go nuts, just delete it and redownload the one here..

Speed-RPM 2.xls

Edited by ISX

Share this post


Link to post
Share on other sites

good work....really easy to use...thanks but what is "Tire Thickness percentage (Required)" and how does that play a role?

The middle of the tire formula (245/75/16) is a percentage... The 245 is the width of the tire in mm's. The 75 tells you how much of the width of the tire the sidewall height contains. As in, from the edge of the wheel to the outer part of the tire, is 75% of 245. Obviously this is America and we need English units so you convert 183.75 (75% of 245) into inches by multiplying that by 0.0393700787, now you have about 7.23", so if you measured the sidewall on that tire (the stock size) it would measure almost 7 1/4". So to get tire height you multiply 7.23 by 2 (since there are 2 sidewalls in tire height) and then add the wheel size of 16". Now you have a 30.5" tire.. Let me know if you don't understand that. Alright I updated the file it to make that part a little clearer. Edited by ISX

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
Sign in to follow this  



×